In 126 postmenopausal women with metastatic breast cancer, four chemotherapeutic combination programs were tested. Patients were stratified and randomized to one of the four programs: (1) fluorouracil, cytoxan and prednisone (CFP): (2) fluorouracil, cytoxan and Adriamycin (CAF); (3) cytoxan and Adriamycin (CA); or (4) alternating combinations of CFP-CA. Objective response rates were 17% for 18 patients on CFP, 25% for 40 patients on CAF, 42% for 41 patients on CA and 63% for 19 patients on CFP-CA. CFP-CA provided a significantly higher response rate than either CFP or CAF. The response rate of CA was intermediate. The duration of remission and survival were similar for all four groups. When progression or relapse following remission was demonstrated, patients were rerandomized to either adrenalectomy or tamoxifen. There were no responders either in the 15 patients undergoing adrenalectomy or the 11 patients receiving tamoxifen. In a crossover study, nine adrenalectomized patients received tamoxifen and four tamoxifen-treated patients underwent adrenalectomy. None responded. It appears that response rates to hormonal modalities are reduced in patients previously treated by combination chemotherapy.